10 Best Magnesium Supplements, According to Registered Dietitians

We evaluated over 30 magnesium supplements in different forms, and the Nutrition Lab experts selected picks based on the following criteria:

✔️ Forms and bioavailability of magnesium: We included a range of magnesium types with attention to absorption and tolerability, recognizing that different forms may vary in how well they are absorbed and how gently the digestive system tolerates them. We also considered the elemental magnesium content to ensure clarity about the actual usable dosage.

✔️ Ingredient quality and formulation: We prioritized products made with high-quality ingredients and minimal additives, favoring formulas free from artificial preservatives, flavors, synthetic dyes, and unnecessary fillers or sweeteners. Where additional ingredients were included, we considered whether they served a clear functional purpose.

✔️ Dietary accessibility and usability: We considered whether products were suitable for a range of dietary needs, including vegan, gluten-free, and allergen-conscious formulations, as well as practical factors such as dosing convenience and ease of daily use.

✔️ Third-party testing and quality standards: We prioritized brands that undergo independent testing through reputable organizations such as USP, NSF, and the Clean Label Project. The experts in the Nutrition Lab also reviewed product labeling, ingredient transparency, and manufacturing practices, with emphasis on testing for heavy metals, pesticides, herbicides, and other potential contaminants, as well as overall label accuracy.

Here are a few key factors to consider when shopping for a magnesium supplement:

✔️ Dose and daily intake: Look at how much elemental magnesium you’re actually getting per serving, not just the total compound weight. Many people already get some magnesium from their diet, so a supplement that stays within or near the Daily Value may be sufficient for general use. Higher doses can be appropriate in certain cases, but may increase the risk of side effects such as diarrhea, nausea, or abdominal discomfort. It is often best to start with a lower dose and adjust as tolerated and based on individual needs.

✔️ Form and delivery method: Magnesium is available in a variety of forms, including capsules, tablets, gummies, liquids, powders, effervescent drinks, oils, and topical applications. Different forms may vary in absorption, tolerability, and convenience. For example, capsules and powders tend to be more common for higher doses, while gummies and flavored drinks may improve palatability but may also contain added sugars or sweeteners. Also consider serving size, as some products require multiple capsules or doses per day.

✔️ Quality and third-party testing: Because supplement regulation is limited in the U.S., third-party testing can provide added reassurance around quality and label accuracy. Look for certifications from organizations such as USP, NSF, or the Clean Label Project, which help verify ingredient integrity and potency, and screen for contaminants such as heavy metals and pesticides. Products that follow Good Manufacturing Practices (GMP) also indicate higher manufacturing standards.

✔️ Safety and interactions: Magnesium supplements may not be appropriate for everyone. Individuals with kidney disease or certain gastrointestinal conditions should consult a healthcare provider before use. Magnesium may also interact with some medications, including proton pump inhibitors and certain antibiotics. If combining magnesium with other minerals, such as calcium, it is important to consider timing and dosage, as they can compete for absorption when taken together in supplemental form.

Magnesium is an essential mineral and electrolyte that occurs naturally in the body and plays a role in a wide range of physiological processes.

As registered dietitian and certified nutrition support clinician Eduardo Wrubel, M.S., R.D., C.D.N., CNSC explained, “Magnesium works as a cofactor in metabolic reactions, contributes to bone structure, and helps regulate electrical activity in the body, allowing systems to function properly. In other words, it acts as a transporter, structural component, and helper in hundreds of biochemical processes involved in maintaining overall health.”

Dietary intake is the primary way to meet recommended needs, which are approximately 310 to 320 milligrams per day for women and 400 to 420 milligrams per day for men. However, intake can vary widely depending on diet quality, and many people fall short of these targets. Magnesium is found in a variety of foods, including leafy green vegetables such as spinach, fruits, whole grains, legumes, nuts, seeds, fish, meat, and even water sources like tap and mineral water.

Low intake over time may be associated with symptoms such as fatigue, muscle cramps, or difficulty with relaxation, though these are non-specific and can have many causes.

As with any supplement, it is best to consult a healthcare provider before adding magnesium to your routine, particularly if you have underlying health conditions or are taking medications that may interact with it.

Magnesium contributes to many functions in the body, so there are many health benefits associated with it. "It helps reduce anxiety, support deep sleep, reduce tension (including aches like headaches, cramps, etc.), helps the heart to pump blood and thus move nutrients, and helps the digestive tract to move better," Koff said. "It also helps build and maintain healthy bone mass."

The recommended dietary intake (RDI) of magnesium for adults is 310 to 420 milligrams per day. "Low levels of magnesium are associated with several chronic diseases," Wrubel said, "but that doesn't necessarily mean that magnesium supplementation will improve symptoms or prevent any of those diseases."

Here are some of the more well-researched health issues that may benefit from magnesium supplementation:

• Bone health: The majority of magnesium is stored in bones, between 55% to 60%. "A consistent amount of magnesium seems to be the most beneficial for bone health," Wrubel said. "Deficiency in this mineral can contribute to osteoporosis by altering the activity of the parathyroid hormone and encouraging low-grade inflammation. A review of multiple studies found that there was a benefit in supplementing with magnesium in terms of bone mineral density and fracture risk."
• Type 2 diabetes: Studies show that adequate versus inadequate magnesium benefits insulin sensitivity. "In one study, 300 milligrams per day of magnesium intake versus a placebo was associated with significant improvements in insulin sensitivity for non-diabetic subjects," Wrubel said. Koff added, "Magnesium acts as a cofactor for enzymes involved with insulin secretion and receptors—this helps prevent and address insulin resistance and Type 2 diabetes."

"While research has indicated that there may be a mild benefit from magnesium supplementation on blood sugar control, more studies are needed for the exact supplementation doses," said certified diabetic educator and registered dietitian Grace Hanlon, MS, RD, CDN, CDE. "The best advice would be to eat a diet rich in magnesium-containing foods that are beneficial for longterm health, weight management and blood sugar control." These foods include avocado, nuts, seeds, leafy greens, and tofu, among others.

• Migraines: Supplementation with magnesium may be helpful in the treatment of migraines. "There is evidence that studies support that a very low level supplementation for migraines may be beneficial (500 milligrams versus the RDI 310 to 420), although more research is needed," Wrubel said.

According to Smiley, true magnesium deficiency is not always easy to identify, and symptoms often overlap with a range of other health concerns. Early signs may include loss of appetite, nausea, fatigue, weakness, muscle cramps, or low energy. More significant deficiencies can be associated with numbness, tingling, abnormal heart rhythms, or neurological symptoms.

However, Smiley cautions against assuming that every symptom points to a magnesium deficiency or the need for supplementation. What may appear to be a nutrient issue can also reflect broader factors such as chronic stress, inadequate sleep, under-eating, restrictive dietary patterns, gastrointestinal issues, medication interactions, or inconsistent access to balanced meals.

According to Smiley, the best time to take magnesium—morning or night—depends on the individual and the reason for use.

If someone is taking it to support relaxation or sleep, evening use may be most beneficial. Others may find it better tolerated when taken earlier in the day with meals. Smiley emphasizes that consistency and individual tolerance matter more than strict timing. Some forms of magnesium may cause digestive discomfort or loose stools, and timing may need to be adjusted for those taking thyroid medications or certain antibiotics due to potential interactions.

As she notes, “I also remind women that supplements should support their life, not become another stressful wellness task to manage perfectly.”

Valerie Agyeman is a registered dietitian specializing in women’s health with over 10 years of experience in clinical nutrition, corporate wellness, and nutrition communications. She contributes to food and supplement testing at the Good Housekeeping Institute Nutrition & Fitness Lab and has covered topics including creatine, gut health, vitamin D, and skin health.

Stefani Sassos is the director of the Good Housekeeping Institute Nutrition Lab, where she oversees all nutrition-related content, product testing, and evaluation. She runs and oversees supplement testing and analysis for Good Housekeeping and has previously covered other supplements, including multivitamins and joint supplements.